Update Woo "Continue as Existing user" screen

[chihsuan]

Close #87633

Proposed Changes

This PR updates the "Continue as Existing user" screen to match the new design.

• Just visual and copy changes, no functionality changes.
• Update font and button colors to match the new Woo.com styles. We're now only using Proxima for header titles. Body copy and buttons are now using Inter.

Before:

After:

Testing Instructions

Test "Continue as Existing user" screen

1. Logg in to WP.com but Log out of Woo.com
2. Go to the Woo Express site creation flow (https://woo.com/start/#/installation > Try Woo Express for free)
3. Observe that the "Continue as Existing user" screen matches the new design (4ixWMlzrxllx93tSFsCW6k-fi-9483%3A13771)
4. Click on "Continue as ..." and observe that you are redirected back to the Woo Express flow

Confirm signup and login screens still look good

1. Use incognito mode
2. Go to the Woo Express site creation flow
3. Observe that signup screen looks good
4. Click on "Log in" and observe that login screen looks good

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• https://wpcalypso.wordpress.com/devdocs/docs/testing/index.md for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-99250

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-99250&env=jetpack

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

App Entrypoints (~41 bytes added 📈 [gzipped])

name         parsed_size           gzip_size
entry-login       +203 B  (+0.0%)      +41 B  (+0.0%)

Common code that is always downloaded and parsed every time the app is loaded, no matter which route is used.

Sections (~36 bytes added 📈 [gzipped])

name             parsed_size           gzip_size
jetpack-connect       +203 B  (+0.0%)      +36 B  (+0.0%)
accept-invite          +30 B  (+0.0%)       +8 B  (+0.0%)

Sections contain code specific for a given set of routes. Is downloaded and parsed only when a particular route is navigated to.

Async-loaded Components (~42 bytes added 📈 [gzipped])

name                          parsed_size           gzip_size
async-load-design-blocks           +203 B  (+0.0%)      +34 B  (+0.0%)
async-load-signup-steps-user        +30 B  (+0.0%)       +8 B  (+0.0%)

React components that are loaded lazily, when a certain part of UI is displayed for the first time.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug update/woo-continue-as-user-screen on your sandbox.

[rjchow]

Reviewing this since I'm working in this area -

Looking sharp! One minor issue: the "OR" isn't vertically centered, i.e its midpoint is above the extension of the two lines beside it

[psealock]

Changes look great and code too 🚀

[chihsuan]

isn't vertically centered

Good eyes! 😆 @rjchow Fixed in a13d054